Decreases risk of heart disease and heart attack
When consumed in low doses, alcohol can reduce blood pressure, though when consumed in excess, in can have the opposite effect. Additionally, alcohol helps to clear fat from the arteries, and reduces the blood’s tendency to clot, Dr. Sam Zakhari, the director of the metabolism and health effects at the National Institute of Alcohol Abuse and Alcoholism said. These effects help to limit the chances of heart disease and heart attack. Inflamed arteries that block blood flow are problematic for the heart, as it doesn’t receive the oxygen it needs. Alcohol consumption encourages smoother blood flow, thus lowering the risk of heart disease. Red wine also has the added effect of lowering cholesterol levels, although that benefit is specific to that beverage, Dr. Robert Gish, of the University of California, San Diego School of Medicine said.

Reduces risk of stroke
For the same reasons that moderate drinking can lower the risk of heart attack, it also reduces risk of certain types of stroke. The most common type or stroke, called ischemic stroke, occurs when a vessel bringing blood to the brain gets “clogged,” Zakhari said. “The alcohol helps the blood go to the brain, and therefore it reduces stroke.” The other type of stroke, hemorrhagic, occurs when blood seeps out of a brain blood vessel. Because alcohol thins blood, it actually makes this type of stroke worse, but because hemorrhagic strokes only account for 20 percent of all strokes, there is still a net benefit, Zakhari said. The benefits of alcohol on heart disease and stroke allow some people to argue that moderate consumption is associated with longer lifespan.
How well you sleep at night
A glass of wine may be a pre-bedtime routine for some, but it’s important to understand how the alcohol affects your sleep. For most people, one serving of alcohol before bed will have no effect on sleeping. But more than one drink might — alcohol helps people fall asleep, but makes it more likely they’ll wake up during the night.

“You will sleep faster, but not better,” because alcohol interferes with REM sleep, Zakhari said. Additionally, people often use an alcoholic drink as a means to fall asleep, particularly if they’ve drank lots of caffeine during the day, Gish said. This combination may seem to work on the surface, but it is not a healthy in the long run, Gish said. He tells patients with sleep problems to cut all alcohol and caffeine out for two weeks to understand where the problems lay.

Slight diuretic effect
Alcohol is a diuretic, meaning that one of its effects is to encourage water to leave the body more quickly. Heavy drinkers can become dehydrated, and people tend to go to the bathroom frequently while drinking. In modest amounts, this slight diuretic effect is not harmful, Zakhari said. However, if a person is already slightly dehydrated before having a drink, perhaps from heat or from working out, the effect will be more apparent. The effect is strongest in beer, Gish said, and is less obvious for hard alcohol or wine. Another reason why drinking alcohol is often associated with being dehydrated is that people tend to snack on salty foods when drinking, which contributes to dehydration, he noted.

Enhances social interactions
While drinking too much is often has a detrimental impact on relationships, drinking moderately can often enhance social interaction, Zakhari said. “It enhances cognition, so it makes people more convivial and enhances social interactions,” he said. For people who drink in a bar, strangers often start conversations, and there are lots of jokes and laughs, he said. However, the change in behavior can go both ways, Gish cautioned. “A lot of believe that alcohol is psychotropic it changes people’s mood states,” he said. It can make them more pleasant, or more irritable, depending on the individual, he added.